Electric furnace.



C. C, WHITMORE.

ELEGTRIG FUBNAGE. APPLIOATION FILED @12.16, 1913.

Patented Mar. 3, 1914.

2 SHBBTS-SHEET L NVENTOR m, NN

Ek Lg ATTORNEYS C. G. WHITMORE.

Patented Mar. 3, 1914.

2 SHEETS-SHEET 2,

ATTORNEYS UNITED STATES PATENT OFFICE.

CLAUDE C. WHITMORE, OF BUTTE, MONTANA, ASSIGNOR OF-ONE-HALF TO WALKER B.CARROLL, OF BUTTE, MONTANA.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented Mal'. 3, 1914.

T 0 all whom t may concern.'

Be it known that I, CLAUDE C. WHIT- MoRE, a citizen of the U itedStates,and a resident 'of Butte, in th county of Silverbow and State ofMontana, have invented an Improvement in Electric Furnaces, of which thefollowing is a specification.

My invention -relates to electric furnaces, and more particularly toelectric furnaces of the kind used for smelting ores.

My invention comprehends a number of .distinct improvements relating tothe construction and operation of electric furnaces of this type, andamong the advantages sought to be accomplished by my invention are thefollowing: I. The utilization of the current in two ways, to Wit, inheating the electrodes and in heating the ores and substances intermixedtherewith by conductivity thereof.l II. To prevent overheating of theelecetrodes. III. T control the distribution of `the ores or othermaterials upon which the furnace operates,a greater amount of materialbeing passed into the furnace at points where the heat thereof iscomparatively great. IV. To enable agroup of electrodes to be readilymoved relatively to another group thereof for purposes of distributingthe current. V. To promote the general efficiency of furnaces of thiskind.

Reference is made to the accompanying drawings-forming a part of thisspecification and in which like letters indicate like parts. v

Figure l is a vertical section through my improved furnace and is takenon the line l-l of Fig. 5, lookin in the direction 'of the arrow. Fig. 2is a front elevation of the furnace complete. Fig. 3 is a detail showingin section one of the joints employed in connection with the electrodes.Fig. 4 is a fragmentary view, partly in elevation and partly brokenaway, showing the feeding mechanism. Fig. 5 is a vertical section on theline 5-5 of Fig. 1, looking in the direction of the arrow.

body is a smoke flue l2 for conveying away the smoke and gases producedduring the operation of the furnace. Mounted upon the top of the furnacebody are hoppers 13, 14, in this instance -two in number, these hoppersbeing supported by aid of standards 15. A revoluble shaft 16 extendsacross the hoppers and is mounted in bearings 17. Secured upon thisshaft 16 are beveled Wheels 18, 19, which mesh with bevel wheels 20, 21,the latter being mounted rigidly upon vertical shafts 22, 23. Theseverticall shafts, at their lower ends, are provided with feed screws 24,2'5,l as will be understood from Fig. 4. The feed screw 25 is of coarserpitch than the feed screw 24 and on this account` supplies material intothe furnace with greater rapidity than does the'screw 24. 'This isbecause the screw 25 being located comparatively near the middle of thefurnace, and at a point where the heat isvery great, tends to supply theorev at a rate commensurate with the rate at which it is likely to beused.

A number of electrodes are shown at 26.

lEach of these electrodes is of cylindrical form and is made of materialoffering comparatively-high resistance to the passage of the electriccurrent. German silver is suitable for the purpose. The slag spout isshown at 26, the metal spout at 27, and the tap hole at 27. Conductingcables 28 are connected with the electrodes 26.

I find it advisable to insulate the ends of 4the electrodes, and forthis purpose I employ an insulating joint which, as a whole, I designateas 29 and which is shown more particularly in Fig. 3. In this joint Iprovide a sleeve 29HL of insulating material, such as clay orearthenware, and bring this sleeve against the adjacent end of aneleotrode 26. Abutting the end of the sleeve 29a. opposite thiselectrode, is a which bends upwardly and thus orms a rounded elbowjoint. Encircling each end of each electrode 26 is a sleeve 31 made ofinsulating material adapted to withstand a high degree of heat. Anothersleeve 32, like the'sleeve 31, engages the opposite end of the sleeve 29and encircles the pipe 30. The electrodes 26 and pipes 30 are providedwith threaded portions 33, 34. Engaging these threaded portions arerings 35, 36, of insulating material serving to some extent as packingsadapted to withstand heat.

ipe 30` Encircling the sleeves 31, 32, are yplates 37 of insulatingmaterial, preferably massive asbestos, and extending through theseplates are tie rods 38 provided with threaded portions 39, and uponthese threaded portions are fitted nuts 40 for coupling the partstogether as indicated in Fig. 3. By employing joints of this kind, eachelectrode 26 -is very effectively connected with a pipe section 30 andat the same time thoroughly insulated from the latter.. Each pipesection 3() is provided with a stuffing box 41 and extending throughthis stuiiing box is a pipe 42 for conveying a cooling medium throughthe pipe section 30 and into the electrode 26. The pipe 42 is providedwith a valve 43 for controlling the -flow of the cooling medium, whichmay be air, water, or any kind of gas or liquid suitable for thispurpose. I nd that if water be used, it should be under the pressure ofat least forty pounds per square inch, and that it may, with advantage,be under a much higher pressure lthan this. Extending downwardly fromeach pipe section 30 is a pipe section 44 provided with a valve 45. Theseveral pipe sections 44 are connected with a pipe section 46 extendingacross the entire width of the furnace, the pipe section last mentionedbeing connected with a pipe section 47 extending lengthwise of thefurnace. Communicating with the pipe section 46 and extending upwardlyfrom the same are a number of pipe sections 48 which extend into, andform telescopic connections with, a number of pipe sections 49. rlheselast-mentioned pipe sections are severally connected with pipe sections50. A number of horizontally disposed pipe sections 51 are provided, asindicated in Fig. 2, these lastmentioned pipe sections each extendingacross from one of the pipe sections 50 to another, The several pipesections 50 are, by aidof joints 29 of the kind above described andshown in Fig. 3, severally connected with a number of electrodes 52.These electrodes have the same structure as the electrodes 26 and extendloosely through slots 53, 54, located respectively in the end walls 11,10, of the furnace body. The electrodes 52 are movable vertically withinlimits permitted by the slots 53, 54. provide sheave pulleys 55, 55, andengaging these pulleys and running between them is a cord 57, the cordand pulleys being supported from horizontally extending beams 56 securedto any appropriate part of the framework or building. The pipe sections-50 are provided at their upper ends with stuffing boxes 58 andextending through these stufling boxes and into the pipe sections 50 arepipes 59 for supplying a cooling medium for conveying the same from thepipe sections: 50, as hereinafter described. The pipes 59 are providedwith valves 60 for controlling the flow of the. cooling medium.Connected with the electrodes 52 are cables 61 orother appropriateinsulated conductors. At the ends of the electrodes 52 opposite thecables 61 are other cables 62. Near the cables 62 are cables 27a whichare connected with the adjacent ends of the electrodes 26.

The ends of the electrodes 26 are, by aid of joints 29 above describedand shown in Fig. 3, connected with pipe sections 63 which extendrearwardly and upwardly. Communicating with the pipe sections 63 andextending directly downward therefrom are'pipe sections 64 which areprovided respectively with valves 65. The pipe sections 63 arc providedwith stuiiing boxes 66 and extending into these stuffing boxes are pipes67 used for conveying the cooling fluid into or out of the electrodes26. The electrodes 52 are connected by joints 29, of the kind abovedescribed, with pipe sections 69. Communicating with these lastmentionedpipe sections and extending downwardly therefrom are pipe sections 70.The pipe sections 69 carry stuffing boxes 71, and extending into thelatter are pipes 72 provided with valves 7 3 and used for controllingthe iiow of the cooling medium. Pulleys 74, 76, connectedby a cord 75and supported by a sustaining member 77, such as a beam, are connectedwith the pipe sections 69 and are used for raising and lowering thesepipe sections, together with the adjacent ends of the electrodes 52. Thepipe sections at the rear of the furnace have telescopic connectionswith the pipe 78 in much the same manner that the pipe sections 49 atthe front of the furnace are telescopically connected with the pipe 46.By manipulating the cords 57, 75, the electrodes 52 may be raised andlowered as desired and may be made to assume slightly different angularpositions relatively to the electrodes 26. Y

Current may be supplied in various ways through the cables 27, 28, 61,62. For instance, ,current may be supplied to both ends of each ofthevelectrodes 52 and caused to travel from these electrodes through thematerials to be smelted to the electrodes 26 and thence out of thefurnace to the source of supply and back to the electrodes 52. ,Agairncurrent may be supplied from a source of supply through cables 61 toelectrodes 52, thence through the materials to bel smelted to theelectrodes 26, thence out through cables 28 to the source of supply. Aseach individual electrode 52, 26, is 'provided with its own particularcables, one at each of its ends, the number'and variety of electricalconnections which can be made is very great. The electrodes may,therefore, be connected l either in series with each other or arrangedinto groups and the groups connected in series with each other andvarious parallel connections may bemade at the will of the operator.Generally, however, I prefer to connect all of the electrodes 52 inparallel with each other and all of the electrodes 26 in parallel witheach other, so that the group of electrodes 52 is in series with thegroup of electrodes 26, and so that the current passes from theelectrodes 52 through the ore mass-to the electrodes 26.

Since the electrodes 52, 26, vare made of heat-resisting metal(preferably German silver as above` stated), the electrodes'arethemselves heated by the passage of the current through the ore and theore itself by virtue of its ohmic resistance is heatedsomewhatindependently of .the thermal effect of the electrodesvu'ponthem; that is toy say, the ore is heated in two ways, to wit, byproximity to the heated electrodes and by the passage through thematerial of a current adapted to heat them in transit. As oresusually'contain more o r less moisture, anderen dry ores frequentlycontain water of crystallization which is driven off during the actionof the furnace, the moisture thus produced increases the facility withwhich the materials are heated by the passage of the electric current.

A cooling medium is supplied through the various pipes 42, 59, 67, 72,and may be distributed in various ways. For instance, it may bedesirable to cause the cooling liquid tomove to the right through theelectrodes 26 according to Fig. 1. To do this, the pipe sections 64 areclosed by aid of the valves 65; the pipes 67 are opened-by the valves68; the pipe sections 44 are opened by turning the valves 45. 'Thecoolllng liquid now enters through the pipes 67 and passes throughoutthe entire length of the electrodes 26, being collected together andmakinr its escape through the pipe section 47. gain, by closing thevalves 45 and opening the valves 43 and 65, the cooling liquid may becaused to moye from right to left, according to Fig. 1, through theelectrodes 26. Similarly, the cooling liquid may be forced in either oftwo directions through the electrodes 52.

As above indicated. I may use 'any variety of cooling fluids. Compressedair is suitable for cooling-and so is water. Generally speaking, Iprefer to use the cooling fluid under comparatively high pressure and incase of using air or gas, Iallow. the pressure of the cooling fluid torelax within the electrodes in order to cause expansion and thuswithdraw heat. Of course, some de.- gree of care is necessary to enablethe operator to ascertain just how hot the electrodes may become-beforethe cooling fluid is turned on. If it be turned on too early, it wastesthe heat of the furnace and if it be turned on too late, the electrodesmay be endangered.

The operation of my device is as follows.'

The parts being assembled and arranged asv Y the middle or center of thefurnace receives more ore than the upper end of the furnace. In thismanner, the various portions of the furnace receive quantities of oreroughly i proportioned to the relative capacities of different portionsof the furnace to dispose of the ore. In other Words, the largestquantities o-f ore are fed to the hottest portions of the furnace. Thecooling uid being now turned on and caused to circulate as abovedescribed and the electriccurrent being also turned on, the ore isheated in the manner above described, partly by the elevated temperatureof the electrodes and partly by thedirect heating effect of the currentin passing through the ores.

Among the ores especially adapted for reduction 1n my improved furnacemay be mentioned all iron ores, the sulfid ores of copper, silver oresof all lrinds, gold ores, lead ores, zinc, mercury and antimony ores.Other ores, however, in Which the electrical conductivity is inferior tothat of the ores just mentioned may be operated upon. In starting thefurnace, and especially in start-- ing with ores of inferiorconductivity, any of the conventional primings may be employed for thepurpose of rendering the ore sufficiently conductive to carry enoughcurrent to begin work. The furnace being once inaction, almost anymaterial thrown into it will, by fusing, become sufficiently conductiveto continue the operation, so long as the` electric current is supplied.

I do not limit myself to the particular construction shown, as variouschanges may bc made therein without departing from the spirit of myinvention.

Having thus described my invention, what I claim asnew and desire tosecure by Letters Patent is as follows 1. An elect-ric furnace,comprising a furnace body provided at its ends with slots, an electrodeof longitudinal form extending through said furnace body, a secondelectrode extending through said furnace body and disposed approximatelyparallel to said first mentioned electrode, said second electrode beingof tubular form, means for cooling said second electrode, and mechanismcontrollable at the will of the operator for adjusting said secondmentioned electrode to different angles relatively to said firstmentioned electrode.

2. An electric furnace, comprising a furnace body, an electrode mountedtherein, a

second electrode located Within said furnace body and movable relativelyto said irst' mentioned electrode, said second-mentioned electrodehaving substantially the form of a long cylinder, means controllable atthe Will of the operator for tiltingI said second-mentioned electrode todifferent angles relatively to'said first mentioned electrode, and meansfor supplying current to both of said electrodes.

3. An electric furnace. comprising a furnace body provided atits endswith slots an electrode extending through said furnace body and throughsaid slots, means controllable at the Will of the operator for raisingand lowering said electrode,another electrode located Within saidfurnace body, and electrical connections to said electrodes.

4. An electric furnace comprising a furnace body, electrodes of tubularform eX- tending into said furnace body and disposed approximatelyparallel with each other, means for supplying a cooling fluid into eachof said electrodes and mechanism controllable at the Will of theoperator-for shiftz.

ing the general position of one of said electrodes relatively to theother.

EMMA V. OBRIEN, ANNIE M. VVHI'TMORE.

